Trash rake

ABSTRACT

The trash rake employs a double-acting hydraulic cylinder positioned between the rake teeth and rake tines. The hydraulic cylinder may be activated to hold the rake in any number of positions between the fully opened and fully closed positions. The rake is positively held in any of the adjusted positions due to the pressurized hydraulic fluid in the cylinder.

[56] References Cited UNITED STATES PATENTS 40,709 11/1863Raymond..................... 212/81 3,038,620 6/1962Collin........................... 294/88 Primary ExaminerHarvey C.Hornsby Attorneys-John P. Hines, Robert B. Benson and Arthur M.

Streich Edwin W. Murphy York, Pa.

Appl. No. 855,112

Sept. 4, 1969 Mar. 30, 1971 Allis-Chalmers Manufacturing CompanyMilwaukee, Wis.

1 Claim, 2 Drawing Figs.

United States Patent [72] inventor [22] Filed [45] Patented [73]Assignee [54] TRASH RAKE ABSTRACT: The trash rake employs adouble-acting hydrau- 294/88, lic cylinder positioned between the raketeeth and rake tines. 294/104, 212/ 135, 212/84 The hydraulic cylindermay be activated to hold the rake in B66c 1/00 any number of positionsbetween the fully opened and fully 294/49, closed positions. The rake ispositively held in any of the ad justed positions due to the pressurizedhydraulic fluid in the cylinder.

[50] Field ofSearch............................................

TRASH RAKE This invention pertains in general to trash rakes and moreparticularly to a trash rake which .is operated by a double-actinghydraulic cylinder.

ln hydraulic installations, such as a hydraulic turbine, a screen isprovided in the water passageway upstream from the operating parts ofthe turbine. The screen is positioned so that all water moving into theturbine must pass through it. The screen is designed so that largepieces of debris, such as logs, which might damage the hydraulicturbine, cannot pass through the screen. Over a period of time, thedebris clogs the screen to the point of interfering with a sufficientflow of water. It is then necessary to provide means to clean thisdebris from the face of the screen.

It is the practice in many hydraulic installations to provide a trashrake to remove the debris from the screen. The rake travels up and downon the screen grating and is usually composed of a series of spacedtines and teeth which are pivoted together at one end thereof. As therake is lowered along the screen, the teeth are open relative to thetines. When the debris is engaged by the tines, means are provided toclose the teeth about the debris holding it between the teeth and thetines. The rake is then raised removing the debris from the screen.

Many difierent mechanisms have been provided to open and close the raketeeth. Most of these are mechanical devices which are operated by cablessuspended from the hydraulic installation above the screen. It isdesirable that this operating mechanism be capable of exertingsufficient force to ensure that the debris will be held in the rake'whenit is raised from the stream.

It is therefore the intention and general object of this invention toprovide a trash rake for a hydraulic installation wherein positivehydraulic force is used to position the rake teeth relative to the raketines.

A more specific object of the subject invention is to provide a trashrake for a hydraulic installation wherein a double-acting hydrauliccylinder is used to selectively position the rake teeth relative to therake tines.

These and other objects of the subject invention will become more fullyapparent as the following description is read in light of the attacheddrawings wherein:

FIG. 1 shows a trash rake constructed in accordance with the invention;and

FIG. 2 is a side view of that trash rake.

Referring to the attached drawing, the water passageway into thehydraulic turbine (not shown) is generally designated 6. A screen havinga plurality of laterally spaced parallel grates 8 is provided across thepassageway 6. The screen 7 is supported by a portion of the hydraulicinstallation superstructure generally designated 9.

The trash rake generally designated 11 is composed of a rake tooth 12and a rake tine 13. As shown herein for purposes of illustration, therake tooth 12 is constructed of a solid steel plate 14 reinforced byspaced ribs 16. The tooth l2 curves at the bottom to engage the tine 13forming a trash retaining space therebetween. Reinforcing straps 17 maybe provided to further strengthen the lower portion of the tooth. Thetine 13 may also be constructed of a solid plate having laterally spacedparallel reinforcing ribs 18. It should be understood that both thetooth 12 and the tine 13 may be constructed with individualclosely'spaced parallel ribs rather than providing a steel plate as isherein shown for purposes of illustration.

The uppermost portions of each of the ribs 16 and 18 are provided withhinge members 19 and 21 respectively. These hinge members have alignedbores therethrough which are pivotally supported on a rod 22. Adouble-acting hydraulic 12 and rake tine 13. As herein shown forpurposes of illustration, the cylinder 23 is pivotally connected to therake tine l3, and the piston rod of the cylinder 23 is pivotallyconnected to the rake tooth 12. lt should be understood that theconnection of the hydraulic cylinder to the rake. could be reversed fromthat shown herein.

An l-beam 24 is rigidly connected to the columns 25 of thesuperstructure 9 of the hydraulic installation. This l-beam ispositioned above and is disposed parallel to the screen 7. Aconventional electric hoist 26 is connected to the l-beam by rollers 27.The hoist cable 28 is connected to a cable pulley 29 which in turn ispivotally connected to the rod 22.

A hydraulic power package generally designated 31 for the cylinder 23 isconnected to the I-beam 24 by means of rollers 32. The power package 31is connected to the electric hoist 26 by means of a connecting bar 33 topermit travel of the power package along the l-beam with the hoist. Apair of springbiased hose reels 34 and 36 are rotatably supported by thehydraulic power package 31 and support hydraulic hoses 37 and 38 whichare connected at one end to the double-acting hydraulic cylinder 23. Thehose reels 34 and 36 are of the conventional type which are springbiased to automatically retract the hoses as slack is provided thereindue to raising the rake 11. The weight of the rake pulling on the hosesas it is lowered overcomes the bias of the spring in the reels to permitthe hoses to unwind. The hoses 37 and 38 are connected respectively toconduit 39 and 41 through a rotational coupling at the center of eachreel as is well known in the art. The conduit 39 and 41 are connected toa conventional two-way slide valve generally designated 42. A sump 43including a hydraulic pump (not shown) is provided to supply pressurizedfluid to the hydraulic cylinder.

In operation the valve42 is moved in one direction to permit pressurizedfluid to enter the conduit 41 and then through the hose 38 activatingthe hydraulic cylinder to open the rake 11 as is shown in phantom linesin Fit 2. The electric hoist is then operated to lower the opened rakewhich slides on the screen 7 until it engages any trash which hascollected thereon. After the trash has been engaged, the valve 42 ismoved in the opposite direction to admit fluid through the hose 37 toretract the hydraulic cylinder piston rod closing the rake andcollecting the trash between the tooth 12 and the tine 13. The electrichoist is then again activated to raise the rake above the water level topermit removal of the trash. As the rake is raised, the tension of thehoses 37 and 38 is removed, thereby permitting the spring-biased reelsto rotate winding the hoses on the reels as the rake is raised.

From the above description it can be seen that a very simplified yethighly dependable trash rake is provided. The hydraulic cylinderprovides positive power positioning of the rake tooth relative to thetines to ensure that the teeth maintain a tight grip on the trash.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

lclaim:

1. A device for cleaning a screen interposed in a flowing stream ofwater to interrupt debris in the water comprising: a rake having a toothand a tine connected at one end for pivotal movement relative to oneanother, said rake being disposed to permit sliding movement of saidtine on said screen; a doubleacting hydraulic cylinder connected betweensaid rake and said tine and operable upon actuation to selectively movesaid tooth away from and into engagement with said tine; overheadhoisting means connected to said rake to raise and lower same along saidscreen; a source of pressurized hydraulic fluid; means operablyconnecting said pressurized fluid source in fluid communication withsaid hydraulic cylinder; and means for selectively directing saidpressurized fluid to said cylinder to operate same.

1. A device for cleaning a screen interposed in a flowing stream ofwater to interrupt debris in the water compRising: a rake having a toothand a tine connected at one end for pivotal movement relative to oneanother, said rake being disposed to permit sliding movement of saidtine on said screen; a doubleacting hydraulic cylinder connected betweensaid rake and said tine and operable upon actuation to selectively movesaid tooth away from and into engagement with said tine; overheadhoisting means connected to said rake to raise and lower same along saidscreen; a source of pressurized hydraulic fluid; means operablyconnecting said pressurized fluid source in fluid communication withsaid hydraulic cylinder; and means for selectively directing saidpressurized fluid to said cylinder to operate same.